In certain electrical connection applications it is necessary to assemble a plurality of cables into a single electrical contact holder assembly mounted in a connector in order to easily connect the latter to an electrical device, for example another connector or electrical unit each provided with a corresponding electrical contact holder assembly. Each individual wire entering the electrical contact holder assembly from a cable is thus connected to at least one contact, which is either a male pin type contact or a female socket type contact that will be subsequently connected to a complimentary male pin type contact or female socket type contact provided on the electrical contact holder assembly of the electrical device to be connected. In some cases one or more of the cables are shielded. Therefore, on the one hand, the problem is one of retaining within the electrical contact holder assembly and the associated connector the impedance as close as possible to the impedance observed in the cables and, on the other hand, ensuring the continuity of the individual shielding of each of the individual wires of the cables inside the electrical contact holder assembly up to the electrical device to which the connector is designed to be connected.
A known solution to this problem consists in substantially conserving the geometry of the cable and the dielectric properties of the materials constituting the cable within the electrical contact holder assembly, and in particular for insulations. As cables generally have an essentially circular cross-section this approach has led to the development of essentially cylindrical electrical contact holder assemblies, which substantially retain the geometry of the cable, as well as the dielectric properties of the materials constituting the cable, with an external shielded shell.
However, in certain aeronautical and military applications the imposed thermal and mechanical constraints limit the choice of materials to those materials having performances which are unsuitable in relation to the performances of the materials used for the cables, notably with regard to the dielectric constants. Two solutions have been proposed to overcome this problem: a reduction in the section of the contacts in the electrical contact holder assembly and an increase in the distance between the contacts in order to limit the differences in the impedance between the cable and the electrical contact holder assembly.
However, reducing the section of the contacts weakens the contacts and makes the contacts more difficult to install and often prevents them from being disassembled. Further, it is preferable to use standardized contacts as it reduces costs, greatly facilitates cabling, and ensures good durability. Additionally, increasing the distance between the contacts disadvantages the useful section inside the electrical contact holder assemblies, as a larger electrical contact holder assembly section is required to dispose the same number of contacts. Designers are therefore faced with three major and problematic constraints: the choice of materials and their properties (notably mechanical, electrical and thermal); the diameter of the contacts to be used; and the spacing between the contacts.
In addition, electrical contact holder assemblies, in particular for aeronautical and military applications, are increasingly subject to detailed standardizations, which define their interface and their geometry, allowing complete and secure interchangeability with electrical contact holder assemblies from various manufacturers. Therefore, a certain number of these standardized electrical contact holder assemblies present a reduced section with a well defined geometry and in particular a rectangular cross-section with rows of contacts which are either male pin type contacts or female socket type contacts, depending on if it is a male or female electrical contact holder assembly.
The solutions proposed for cylindrical electrical contact holder assemblies are therefore not applicable to these electrical contact holder assemblies, since in the case of an increase in the distance between the contacts it is not possible to retain a sufficient number of contacts in the electrical contact holder assembly to ensure the connection of several cables, and, in the case of a reduction in the section of the contacts the restrictions imposed by the standards, notably the aeronautical and military standards in terms of mechanical resistance, will no longer be followed.
Furthermore, it is impossible for designers to selectively dispose contacts in a geometrically shaped section and for a given size to avoid coupling problems. Moreover, the external shielding of an electrical contact holder assembly using an existing accessory does not allow the selective shielding of certain contacts inside the same electrical contact holder assembly. A shielding element which is added to the outside of a electrical contact holder assembly will interfere with the areas of the electrical contact holder assembly designed for locking, coding and sealing which are otherwise often standardized.